German Pat. No. 22 53 074 and the corresponding U.S. Pat. No. 3,915,692 disclose a method of pyrometallurgical processing of fine-grained solids to make products which are molten at processing temperatures.
In that process the solids, suspended in high-oxygen gases, are reacted in a vertical combustion path, in which they are moved at a high velocity to prevent backfiring.
The resulting suspension contains mainly molten particles and is fed into a horizontally extending cyclone chamber. Hot gas, which contains molten droplets, from the vertical cylindrical combustion path directly enters the horizontal cylindrical cyclone chamber at one end of the latter in a tangential direction and centrally leaves said cyclone chamber at its opposite end through a collar to enter a downstream secondary chamber.
The molten material which has been separated out from the gas in the cyclone flows out the exit end for the gas stream into the secondary chamber through a high narrow slot which is formed in the end wall in the vertical center plane thereof below the collar.
A melting cyclone chamber is used in a similar process in German Pat. No. 20 10 872 and the corresponding Canadian Pat. No. 926,631. That melting cyclone chamber has an approximately horizontal axis, which has a downward inclination not in excess of about 30.degree. from the horizontal.
A separate combustion path is not employed and solids and preheated gas are blown into the cylindrical cyclone chamber from above along a secant. Charging is effected almost over the entire length of the cyclone. Through a collar, which has been centrally provided in the end wall, the gas flows into a secondary chamber. The molten material flows under the collar through a hole at the lowermost point of the end wall into the secondary chamber as well.
Depending upon the nature of the solids being processed, trouble frequently can arise during the operation of these cyclone chambers.
Operation at high throughput rates can result in strong incrustation at the gas outlet openings because there the molten material may not any longer be sufficiently separated from the gas.